1. Field of the Invention
The present invention relates generally to computer graphics and animation, and more specifically to the use of normal maps in lighting pixels when rendering three-dimensional computer models in real-time.
2. Discussion of the Related Art
The process of per-pixel lighting in a three-dimensional computer model uses the surface normal and the light vector at each pixel to calculate the brightness of the pixel. A surface normal is like an arrow that points in the direction that the surface of the model is facing. A light vector is a line from the point on the surface to the position of the light. As the angle between the surface normal and the light vector gets greater, the color of the pixel gets darker (and vice versa).
Texture mapping is the process of applying a texture, i.e. an image, to the surface of a computer model during rendering wherein the texture gets mapped onto the surface. The surface normal at each pixel is used along with the color values in the texture map to determine the lighting for each pixel.
A normal map is similar to a texture map but includes surface normal data instead of color values. More specifically, a normal map includes data that alters the original surface normals of the model.
It is with respect to these and other background information factors that the present invention has evolved.